Flour sifter



I 1952 E DENNIS 0 FLOUR SIFTER Filed Jan. 26, 1948 E ucfim Den/7 7'5Patented Aug. l9, 1952 FLOUR SIFTER E LucianDennis, Rockford, 111.,assignor to The Washburn Company, Worcester, Mass, a corporation ofMassachusetts Application January 26, 1948, Serial No. 4,253

' f 6 Claims. (01. 209-357) This invention relates to improvements inflour sifter.

It has been a problem in the manufacture of flour sifters, where theagitators are arranged to be oscillated by means of an oscillatablehandle linked by a connecting rod to the crank that oscillates theagitators, to avoid havingthe crank reach a dead-center position or tooclose to such a position. thereby interfering with easy operation of theoscillating handle, this problem being aggravated because of the loosefit and consequent play between the parts, and also because of theinability generally to work to any closer limits in the quantityproduction of such utensils, and also because of the fact that theagitators are turned quite rapidly back and forth and are accordinglyapt to be thrown to or past a deadcenter position if the play issumcient to permit.

It is, therefore, the principal object of my invention to provide animproved form of crank element having on the outer end of the armthereof a pair of stops spaced for positive engagement with theconnecting rod in the two limit positions of the crank arm forpositively limiting the swing of the crank soas to avoid the. objectionsmentioned. I

Another object is to provide a crank element made from a single strip ofsheet metal formed to provide: 7

(l) A shaft for turning the, agitators;

(2) A crank arm formed by a right angle bent end portion of the strip;

.(3) A pair of stop shoulders formed by bending the outer end of thecrank arm to U-shaped form, and

(4) An easily twistable T-s-haped end portion on the end of the shaftportion remote from the crank arm, which, when twisted into a plane atright angles to the plane of the rest of the shaft portion, serves toprevent endwise displacement of the shaft from assembled relationship tothe agitators.

Theinvention is illustrated in the accompanying drawing, in which- Fig.l is a central vertical section through a flour sitter, embodying theaforesaid improvements of my invention;

Fig. 2 is a bottom view of the sifter, indicating in dotted lines theopposite extreme position of the crank arm from that appearing in fulllines;

Fig. 3 is a perspective viewof the one-piece, sheet metal crank elementprior to its assembly in asifter;

Fig-f is a plan viewv of. the hub portion of the uppermost agitator,showing how the twisted end Fig. 5 is a sectional detail on the line5.5. of

Fig. 4.

The samereference numerals areapplied to corresponding parts throughoutthe views.

Referring to Figs. land 2, the sifter comprises a sheet metal body orcontainer 6 of tubular form, open at the top and bottom, and having aseries of screens I mounted therein in spaced parallel relation. Eachscreen is part of a separate sieve unit,. of which there are three inthe present sifter, the screens being assembled in sheet metal rings 8.made to fit closely inside the container, each screen beingc'linched atits outer edges by the inwardly curled lower edge Set the ring. -Adiametrically extending brace strip 10f sheet metal, which is preferablyribbed longitudinally as at ll for stiffening and, to resist bending, sprovided under the screen 1 of each sieve for sup: port thereof, thestrip being in turn supportedat its ends on top of the curled edge 9ofthe ring, as shown, andbeing furthermore pierced atits mid-point andsecured to the center of the screen associated therewith by means of acircularv grommet oreyelet, 12, whereby to hold the brace per manentlyin the position described, Two diametrically opposed sheet, metal clipsl3 that, are preferably; riveted to the wall ofthe container, as at I4,serve to hold the three sieves in place in the container, with the topsieve disposed in abutment with the annular shoulder l5 defined in thebore of the container by a bead formed in the wall in the manner shown.A hexagonal-agitator l6 cooperates with each screen i, and the group ofagitators is oscillated by meanspof the, shaft portion I? of the crankelement.,showninFig fi and designated generally by the referencejnuemeral l8.- This crank element has a crank arm It pivotally. connected atits specially, shaped outer end portion 20 with the front end portion ofa wire or rod link 2|, which in turn is pivotally connected at its rearend with the lower endpf a stamped sheet metal'trigger or lever 22 foroscillation of all of the agitators VI 8 in unison upon oscillation ofsaid trigger. The trigger is operated by the fingers of the operatorshand that graspsthe handle 23, the trigger being disposed in forwardlyspaced relation tothe-handle-for that purpose, as clearly appearsinyFig; 1; ;:In that figure it will be noticed that the 'handle;23,-which may beof wood or composition or plastic material, is rivetedat'its" upper endfas at 24,1 in the rear end of a sheet metal channel"member 2 5, that is suitably secured atits' front end to the wall of thecontainer 6, the lower end of the handle being riveted, as at 26, in therear end of a U-shaped sheet metal yoke 21, in front of the crossportion of the U, and the front ends of the arms of the U being suitablysecured to the wall of the container. The trigger 22 is pivoted relativeto the handle structure at its upper end on a cross-pin 28 thatsupported at its opposite ends in the opposed side walls 29 of thechannel 25. A bowed leaf spring 30 has one end set in a recess 3|provided in the front of the handle 23 and bears at its other endagainst the shoulder 32 formed on the back of the trigger 22 near itsupper end. The spring is held against lateral displacement from thehandle structure by having its arched middle portion disposed betweenthe side walls 29 of channel 25, as shown. The link 2| extends freelythrough a hole 33 in the wall of container 6 and has its rear endportion bent downwardly to provide the pivot pin portion 34 'for'pivotalconnection with the lower U-shaped end portion 35 of the trigger 22. Ahole 36 is provided in the substantially vertical cross-portion of the Uthrough which the wire link 2| extends freely, and thereis another hole31 in the lower substantially horizontal arm of the U through which thebent pivotal end portion 34 of the wire link projects. The lower end 35of the trigger is threaded onto the. end 34 of the link 2| before thetrigger is assembled in the handle structure. Thereafter the partsdescribed cannot become disassembled, no matter how vigorously thesifter is operated.

In operation, when the trigger'22 is pressed or squeezed and is therebymoved toward the handle 23 against resistance of spring 30, the link 2|moving with it slides freely in the hole 33 and moves crank arm l9 andthe set of agitators |6 with it through an angle of approximately 100 ormore, as indicated by the dotted moved position of the crank arm l9 inFig. 2. When the trigger 22 has been moved as far as it will go, ornearly so, finger pressure thereon is released and thespring 30 returnsthe trigger and the aforesaid parts thereto attached to their startingpositions. The operation is smooth and quiet and consumes very littleenergy so that the operator is not fatigued. The improved constructionof the crank element |8 improves the operation by eliminating anypossibility of the crank arm l9 reaching a dead-center position relativeto-link 2|, or so close to such a relationship, which would interferewith smooth and easy operation. This is because of the positive limitingof relative movement of these two parts l9 and 2| angularly withrespect-to one another, as shown in their two extreme positions in Fig.2. The sheet metal strip of oblong rectangular transverse-section, fromwhich the crank element |8 ismadeis formed between dies to offset theouter end portion-20 in parallel relation'to the rest'oflthe crank armI9 and at the same time define transverse walls 38 and 39' at oppositeends of said ioifs'et portion in planes at right angles to the planes oftheinner and offset outer endportions of the crank arm. These walls alsolie oblique to each other aswell as oblique to the axis of the 'cra'nk'arm, have a length as measured horizontally at least equal to the broadside of the crank arm and are arranged in a horizental .V openingtin thegeneral direction of the handle as most clearly appears in Figs. 2 and3. A'thole40 is'punched'in the offset end portion which can be termedthe weblinking the two walls,38, 39, the hole lllzbeing locatedequidistant between these walls, and the wire link 2| has an upwardlybent end 4| entered freely in this hole to provide the pivotalconnection between the link 2| and crank arm IS. The upwardly bent end4| is bent again at right angles to provide an arm 42, which, with thepivot 4|, defines a hook on the end of the link 2| that will not becomedisconnected from the crank arm |9 when once properly connectedtherewith, the arm 42 serving also by abutment with walls 38 and 39 todefine the opposite limits of movement of the parts l9 and 2|. In theassembling of the sifter at the factory the arm 42 can easily be bent tothe right or left relative to the rest of the link 2| if a test showsthat the arm l9 and link 2| otherwise come too close to a dead centerrelationship at the one or the other limit position. Such an adjustmentcan be made with a pair of pliers and when once made at the factory willnever be apt to require any further attention,'because the trigger 22 isnot operated with suificient force to give rise to danger of the arm 42getting bent out of the angle set at the factory.

In conclusion, it will be noticed that the shaft portion llof the crankelement I8 is reduced in width slightly in relation to the crank arm endwhereby to define shoulders 43 for abutment with the eyelet l2 on thelowermost screen to prevent upward displacement of the crank element l8from assembled position. The shaft portion of the crank element fitsnonrotatably in the diametrical slots 44 molded in the hubs 45 of theagitators [6, which, as stated before, are molded in one piece ofplastic material to the final form desired, so that no machining isneeded The upper end of the shaft portion I1 is notched out on bothsides, as at 46, to form an easily twistable T portion 41 for securingthe crank element l8 in assembled relationship to the uppermost agitatorand preventing downward displacement thereof from assembled position, asshown in Figs. 1, 4 and 5. This novel one-piece construction of thecrank element means quite a reduction in the number of parts needed forthe sifter and, besides making for lowered cost of production, makes forcloser uniformity in quantity production, and a truly higher qualitydevice in the final analysis. The one-piece plastic construction of theagitators is of advantage in eliminating any danger of these partsrusting after they have been in service for a time. This constructionalso enables specially shaping the hub portion to obtain improvedperformance. For example, it will be seen in Fig. 1 how the increasedaxial length of the hubs insures keeping .:the two lower agitators inthe desired spaced relation to the screens above so that they remain inthe desired close working relationship to the screens therebeneath foreficient sifting, the uppermost agitator being, of course, held down onits screen by the twisted end 41 of the shaft portion Next, notice inFig. 5 the downwardly projecting annular bead 48'formed on the bottom ofthe hub portion 45 of each agitator arranged to ride on top of thescreen therebeneath around the eyelet I2 and support the agitator at apredetermined small elevation relative to the screen for most efilcientsifting. Also, note the recess 49 in the bottom ofzthe hub for receptionof the eyelet |2 with ample operating clearance. The bead 48 and recess49 together insure proper relationship of each agitator to the screenassociated therewith. It is believed the foregoing description conveys agood understanding of the objects and advantages of my invention. Theappended claims have been drawn to cover all legitimate modificationsand adaptations.

I claim:

1. As an article of manufacture, a combination agitator drive shaft andoperating crank member for a flour sifter and the like, comprising aone-piece elongated sheet metal body of oblong substantially rectangulartransverse section bent to define a vertical shaft portion adapted tofit non-rotatively in a similarly shaped opening in the agitator, and acrank arm portion extending transversely with the broad side thereof ina horizontal plane, the outer end portion of said crank arm being bentobliquely to the axis of the crank arm to establish a pair of wallsformed by the broad side of said crank arm and which walls are arrangedsubstantially as a horizontal V with a web portion ,therebetween, saidweb portion being provided with an aperture equidistant between saidwalls to provide a pivotal connection between said crank arm and the endportion of an actuating link therefor, the said end portion of the linkbeing oscillatable between said walls at the wide open end of the .V.

2. An article of manufacture as set forth in claim 1, wherein the shaftportion of the body is of reduced width in relation to the rest of thebody throughout the major portion of its length so as to define, nearthe crank arm, opposed shoulders for location of the shaft portionendwise with respect to a sifter element in the assembling of the partin a sifter.

3. An article of manufacture as set forth in claim 1, wherein the shaftportion of the body is of reduced width in relation to the rest of thebody throughout the major portion of its length so as to define, nearthe crank arm, opposed shoulders for location of the shaft portionendwise with respect to a sifter element in the assembling of the partin a sifter, the shaft portion being notched on opposite sides near thefree end thereof to provide a short portion of reduced width that may beeasily twisted so as to permit disposition of the extremity of saidshaft portion in transverse relation to the rest of the shaft portion tolocate the shaft portion endwise in relation to an agitator part of asifter.

4. In a manually operable flour sifter, comprising a container having anopen top and bottom and equipped with a handle on the side, a siftingscreen extending transversely in said container over which an agitatoris disposed and adapted to be turned, and a trigger oscillatablerelative to the handle and reciprocating a pushpull link adapted tooscillate a crank to oscillate the agitator, the improvement whichconsists in a combination agitator drive shaft and operating crankmember comprising a one-piece elongated sheet metal body of oblongsubstantially rectangular transverse section bent to define a verticalshaft portion and on the lower end thereof a crank arm portion extendingtransversely with the broad side thereof in a horizontal plane, saidshaft portion being adapted to fit non-rotatively in a similarly shapedopening in the agitator, the outer end portion of said crank arm beingbent obliquely tothe aXis of the crank arm to establish a pair of wallsformed by the broad side of said crank arm and which Walls are arrangedsubstantially as a horizontal Vv with a web portion therebetween, saidweb portion being provided with an aperture equidistant between saidwalls for receiving and establishing a pivotal connection for thecorresponding end portion of said aforesaid push-pull link and. whichend portion is oscillatable between said broad-sided walls which serveas stops therefor.

5. A flour sifter as set forth in claim 4, wherein the shaft portion ofsaid combination drive shaft and crank member is of reduced width inrelation to the rest of the member throughout the major portion of itslength so as to define, near the crank arm, opposed shoulders forlocation of the shaft portion endwise with respect to a sifter screen inthe assembling of the part in the sifter.

6. A flour sifter as set forth in claim 4, wherein the shaft portion ofsaid combination drive shaft and crank member is of reduced width inrelation to the rest of the member throughout the major portion of itslength so as to define, near the crank arm, opposed shoulders forlocation of the shaft portion endwise with respect to a sifter screen inthe assembling of the part in the sifter, the shaft portion beingnotched on opposite sides near the free end thereof to provide a shortportion of reduced Width that may be easily twisted so as to permitdisposition of the extremity of said shaft portion in transverserelation to the rest of the shaft portion to locate the shaft portionagainst endwise displacement in a downward direction in relation to theagitator.

E LUCIAN DENNIS.

REFERENCES CITED UNITED STATES PATENTS in the Number Name Date 408,780Wilsey Aug. 13, 1889 464,416 Benson Dec. 1, 1891 619,166 Gragert Feb. 7,1899 1,002,343 Wantling Sept. 5, 1911 1,070,824 Lehrmann Aug. 19, 19131,488,306 Adams Mar. 25, 1924 1,802,923 Melish Apr. 28, 1931 2,015,087Rafton Sept. 24, 1935 2,153,879 Andrews et al Apr. 11. 19 9 2,181,718Arnold Nov. 28, 1939 2,204,920 Bailey June 18, 1940- 2,244,186 BraunJune 3, 1941 2,314,186 Zuck Mar. 16, 1943 FOREIGN PATENTS Number CountryDate 430,048 Great Britain June 12, 1935

